/*
 * Copyright (c) 2001-2002, David Janssens
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "tgt.h"
#include "bio.h"
#include <stdlib.h>
#include <stdio.h>

/* <summary> */
/* Reset tag-tree. */
/* </summary> */
void tgt_reset(tgt_tree_t * tree)
{
  int i;
  /* new */
  if (!tree || tree == NULL)
    return;

  for (i = 0; i < tree->numnodes; i++) {
    tree->nodes[i].value = 999;
    tree->nodes[i].low = 0;
    tree->nodes[i].known = 0;
  }
}

/* <summary> */
/* Create tag-tree. */
/* </summary> */
tgt_tree_t *tgt_create(int numleafsh, int numleafsv)
{
  int nplh[32];
  int nplv[32];
  tgt_node_t *node;
  tgt_node_t *parentnode;
  tgt_node_t *parentnode0;
  tgt_tree_t *tree;
  int i, j, k;
  int numlvls;
  int n;

  tree = (tgt_tree_t *) malloc(sizeof(tgt_tree_t));
  tree->numleafsh = numleafsh;
  tree->numleafsv = numleafsv;

  numlvls = 0;
  nplh[0] = numleafsh;
  nplv[0] = numleafsv;
  tree->numnodes = 0;
  do {
    n = nplh[numlvls] * nplv[numlvls];
    nplh[numlvls + 1] = (nplh[numlvls] + 1) / 2;
    nplv[numlvls + 1] = (nplv[numlvls] + 1) / 2;
    tree->numnodes += n;
    ++numlvls;
  } while (n > 1);

  /* ADD */
  if (tree->numnodes == 0) {
    free(tree);
    return NULL;
  }

  tree->nodes = (tgt_node_t *) malloc(tree->numnodes * sizeof(tgt_node_t));

  node = tree->nodes;
  parentnode = &tree->nodes[tree->numleafsh * tree->numleafsv];
  parentnode0 = parentnode;

  for (i = 0; i < numlvls - 1; ++i) {
    for (j = 0; j < nplv[i]; ++j) {
      k = nplh[i];
      while (--k >= 0) {
	node->parent = parentnode;
	++node;
	if (--k >= 0) {
	  node->parent = parentnode;
	  ++node;
	}
	++parentnode;
      }
      if ((j & 1) || j == nplv[i] - 1) {
	parentnode0 = parentnode;
      } else {
	parentnode = parentnode0;
	parentnode0 += nplh[i];
      }
    }
  }
  node->parent = 0;

  tgt_reset(tree);

  return tree;
}

/* <summary> */
/* Destroy tag-tree. */
/* </summary> */
void tgt_destroy(tgt_tree_t * t)
{
  free(t->nodes);
  free(t);
}

/* <summary> */
/* Set the value of a leaf of the tag-tree. */
/* </summary> */
void tgt_setvalue(tgt_tree_t * tree, int leafno, int value)
{
  tgt_node_t *node;
  node = &tree->nodes[leafno];
  while (node && node->value > value) {
    node->value = value;
    node = node->parent;
  }
}

/* <summary> */
/* Encode the value of a leaf of the tag-tree. */
/* </summary> */
void tgt_encode(tgt_tree_t * tree, int leafno, int threshold)
{
  tgt_node_t *stk[31];
  tgt_node_t **stkptr;
  tgt_node_t *node;
  int low;

  stkptr = stk;
  node = &tree->nodes[leafno];
  while (node->parent) {
    *stkptr++ = node;
    node = node->parent;
  }

  low = 0;
  for (;;) {
    if (low > node->low) {
      node->low = low;
    } else {
      low = node->low;
    }

    while (low < threshold) {
      if (low >= node->value) {
	if (!node->known) {
	  bio_write(1, 1);
	  node->known = 1;
	}
	break;
      }
      bio_write(0, 1);
      ++low;
    }

    node->low = low;
    if (stkptr == stk)
      break;
    node = *--stkptr;
  }

}

/* <summary> */
/* Decode the value of a leaf of the tag-tree. */
/* </summary> */
int tgt_decode(tgt_tree_t * tree, int leafno, int threshold)
{
  tgt_node_t *stk[31];
  tgt_node_t **stkptr;
  tgt_node_t *node;
  int low;

  stkptr = stk;
  node = &tree->nodes[leafno];
  while (node->parent) {
    *stkptr++ = node;
    node = node->parent;
  }

  low = 0;
  for (;;) {
    if (low > node->low) {
      node->low = low;
    } else {
      low = node->low;
    }
    while (low < threshold && low < node->value) {
      if (bio_read(1)) {
	node->value = low;
      } else {
	++low;
      }
    }
    node->low = low;
    if (stkptr == stk) {
      break;
    }
    node = *--stkptr;
  }

  return (node->value < threshold) ? 1 : 0;
}
